Cold rolling pipe roller type rolling stand

ABSTRACT

A rolling stand with a reciprocating rigid frame carriage coupled to a vertical rocking beam lever for drive reciprocation. The carriage has eight rollers, cooperating with rigid tracks, disposed to maintain the carriage against pitch. A thick walled rolling reduction head is removably and securely mounted in the carriage. The head contains working rollers maintained in a resiliently biased balanced disposition in a slide race or separator so the rollers bear against former tracks rigidly secured against axial shift in the reduction head. The separator is reciprocable and its movement is synchronized, via a connection to the rocking lever, with the reciprocation of the head so the separator follows the movement of the rollers relative to the head. A wedge mechanism under the former tracks enables radial adjustment of the tracks.

United States Patent Tselikov et al. 1 July 4, 197 2 54] COLD ROLLINGPIPE ROLLER TYPE 3,411,336 11/1968 Wadleck ..72/2o9 ROLLING STAND1,890,803 12/1932 Coe ..72/208 [72] Inventors: Alexandr lvanovich Tselikov; Vsevolod primary Examine, Mi|ton Mehr Vladrmrsovrch Nosal; VadlmAnatollevich s h N l N l Ni g K Verderevsky, all of Moscow, USSR.

[73] Assignee: Vsesojuzny Nauchno lssledovatelsky and [57] ABSTRACTproqkmokmstmkmfsky [minute Metal A rolling stand with a reciprocatingrigid frame carriage coulurglcheskogo Mashmostmemya, Moscow, pled to avertical rocking beam lever for drive reciprocation. The carriage haseight rollers, cooperating with rigid tracks,

[22] Filed: Jam 5, 1970 disposed to maintain the carriage against pitch.A thick walled rolling reduction head is removably and securely mountedin [21] Appl. No.: 720 the carriage. The head contains working rollersmaintained in a resiliently biased balanced disposition in a slide raceor 52 U.S.Cl separator so the rollers bear against former tracks rigidlyE d Int CI secured against axial shift in the reduction head. Thesepara- [58] Field of Search 'b 214 210 tor is reciprocable and itsmovement is synchronized, via a connection to the rocking lever, withthe reciprocation of the 56 head so the separator follows the movementof the rollers rela- 1 References Cited tive to the head. A wedgemechanism under the former tracks UNITED STATES PATENTS enables radialadjustment of the tracks.

2,161,065 6/ l 939 Krause ..72/209 36 Claims, 19 Drawing FiguresPATEN'E'EDJUL 41972 3,673,840

SHEEI 10$ 7 INVENTORS ALEXANDR IVANOVICH TSELIKOV VSEVOLD VLADIMISOVICHNOSAL VADIM ANATOLIEVIGH VERDEREVSKY ATTORN PATENTEDJULM 1912 3, 673.840

SHEET 2 or 7 INVENTORS ALEXANDR IVA ICH TSELIKOV OLD VLA OVICH AL MANATOLIEVICH VE EVSKY ATTO PATENTEDJUL' 41972 3,673,840

FIG 3 INVENTORS ALEXAN DR IVANOVICH 'ISELIKOV VSEVOLD VLADIMISOVICHNOSAL VADIM ANATOUEVICH VERDEREVSKY ATTORNE S PATEiHiZDJULM 1572 SHEET 80F 7 IN VEN TORS ALEXANDR IVANOVICH TSELlKOV VSEVOLD VLADIMISOVICH NOSALFIG. I0 VADIM ANATOLlEVlCH VERDEREVSKY fl%am %%4%MQ ATTORN YSPLKTENTEDJULd m2 sum 7 or 7 3,673,840

ANGLE IN DEGREES INVENTORS ALEXANDR IVANOVICH TSELIKOV FIG [7 VSEVOLDVLADIMISOVICH NOSAL VADIM ANATOLIEVICH VERDEREVSKY wwwww y/ ATTORNEYSCOLD ROLLING PIPE ROLLER TYPE ROLLING STAND CROSS-REFERENCE TO RELATEDAPPLICATION The inventive subject matter herein is disclosed but notclaimed in a related US. application Ser. No. 529, filed Jan. 5, 1970,directed to an overall mill structure and method of cold rolling thinwalled pipe.

BACKGROUND OF THE INVENTION Most pipe mill rolling stands are of thePilger roll type although mill rolling stands with rollers rolling alongformer tracks or gibs to provide the reductionof thickness of pipe wallswere known prior to the present invention. Pilger type roll stands aremassive, expensive and require substantial amounts of time forinstallation, removal and replacement because of the criticalcorrelations between varying roller former grooves. The rolls are largeand require heavy load resisting bearings and complex synchronizingmechanism.

On the other hand, roller type roll stands are not as massive and do notrequire bearings for the simple rollers which use straps or bars astracks which provide the roll reduction movement.

Roller type roll stands for cold rolling thin wall pipes have beenpreviously known and constructed and some initial constructions weredisclosed in the text "Cold Rolling Pipe Mills" by Shebakin, Yu. A. etal., Metalurgizdat 1966 published in the Soviet Union. Since thatpublication, the roller type roll stands as well as the drive linkagefor cold rolling thin walled pipes have undergone considerabledevelopment with resultant important improvements in the drive linkageas well as the roll stand and its components.

SUMMARY The present invention pertains to improvements in the carriageof a'roller type of roll stand to provide a simple yet rigid carriagestructure with load and pitch rollers on a lengthened wheelbase over theprior art roll stands as well as an improved drive connection. Theroller head has been made in a simplified manner with roller, straptrack, separator and track adjustment components assembled in athick-walled steel cylinder which has enabled a very simple means ofremovably rigidly locking the head in the carriage. An improved rockinglever assembly has enabled a better balanced drive force to the rollstand from the power equipmentas well as reducing the lateral andvertical dimensions of the pipe mill at the roll stand end. An improved,and more reliable, parallel roll stand end. An improved, and morereliable, parallel roll stand and roller separator linkage has beendeveloped in connection with the new carriage and new rocking leverstructure. Also a novel spring balancing arrangement has been providedfor mounting the rollers in their separator.

The above reiterated new developments and improvements in roll standstructure and operating linkage constitute the principal inventiveaspects of the roll stand invention.

Further novel features and other objects of this invention will becomeapparent from the following detailed description, discussion and theappended claims taken in conjunction with the accompanying drawings:

BRIEF DESCRIPTION OF DRAWINGS A preferred structural embodiment of thisinvention is disclosed in the accompanying drawings, in which:

FIGS. 1a and 1b, viewed together will be referred to as FIG. 1 whichillustrates in side elevation a pipe mill incorporating a roll stand andoperating linkage made in accord with this invention;

FIGS. 2a and 21;, also viewed together will be referred to as FIG. 2,illustrating in plan view the pipe mill seen in FIGS. la and 117;

FIG. 3 is a diagrammatic representation .of the power and driventransmission mechanism in the mill shown in FIGS. 1 and 2;

FIG. 4 (on sheet 2) is an illustrative drawing of the Geneva feed usedin the feeding and turning mechanism;

FIG. 5 is a sub-assembly side elevation of the roller carriage andattached rocking lever, the lever being partially broken away;

FIG. 6 is a vertical section view taken on line 6-6 of FIG. 7, showinginternal details of the rolling stand as well as added details of theoperating rocking lever and connecting links;

FIG. 7 is an enlarged, partially sectioned, rear end view of the rollercarriage, the rocking lever and operating links;

FIG. 8, drawn to a smaller scale than FIG. 7, is a front end view of theroller carriage with one ofthe carriage support rollers shown insection;

FIG. 9, a vertical section view taken on line 9-9 of FIG. 6, illustratesinterior details of the roller carriage;

FIG. 10 is an enlarged detail section of the separator cage, shown insmaller scale in FIG. 6, illustrating the spring balanced rollermounting;

FIGS. 11 and 12 are somewhat diagrammatic views, respectively showing anarrangement using three rollers and an arrangement using five rollers;

FIG. 13 is a pictorial perspective view showing just the three rollersand their strap tracks;

FIG. 14 is an exaggerated contour view of the roller track profile on astrap;

FIG. 15 is pictorial side view illustrating the the rolling operation;

FIG. 16 is a front view of a roller drawn to scale and used toillustrate the degree of rolling out of the edge of the roller when a 2mm reduction in diameter from a stainless steel pipe blank to finishedpipe is being accomplished; and

FIG. 17 is a graph used in determining rolling out angles for rollersused in cold rolling of stainless steel pipe.

SPECIFIC DESCRIPTION With reference to FIGS. 1 and 2, a pipe mill willbe generally described in terms of its main mechanisms and details ofthe roll stand and its operating linkage will be described hereinafterwith reference to FIGS. 5-17, most of which are reproduced from workingdrawings and can be scaled for relative dimensions. As the generaldescription proceeds, by referring to the diagrammatic illustration ofFIG. 3, the functional interrelationship of the mechanisms can bekinematics of better understood.

The pipe mill 50 disclosed in the drawings has been used in producingthin-walled pipe with CD. of from '8-15 mm. The mill is assembled from anumber of sub-assemblies supported by the mill floor or foundation 52.Main power is furnished by an electric drive motor 54 which can belocated in a well 56 under the other pipe mill components which aresupported on several heavy steel I-beams 58 resting on and secured tothe mill floor. A rolling stand 62 is located at the front end (righthand end of the drawings) of the mill and, with the rocking leverassembly 64, is mounted in a front mill housing 66 in a manner enablingthe rolling stand to be reciprocated back and forth by the rockinglever, as will be hereinafter described in more detail. The fronthousing contains heavy structural steel framework secured to the I-beambed.

At the left-hand end of the mill, a rear housing 68, also secured to thel-beam bed, contains feeding and turning gear mechanism 70, a part ofthe drive'path from motor 54 to the mandrel clamp assembly and thefloating blank chuck 80. The front and rear housings 66 and 68 arerigidly secured to and provide end support for the intermediate frame ormill table 72 which includes a heavy cast rear end brace 74 and parallellongitudinal beams 76 to which are fastened parallel channel trackslideways 78 forming guide tracks for a floating" blank feed chuck 80which travels from a position adjacent the rear housing to a locationadjacent the front housing in feeding a pipe blank to the rolling stand.

Seen between the main motor 54 and front housing .66 is a third housing82, offset to one side but rigidly secured to the I- beam bed. Housing82 contains reduction and drive transfer gearing from the motor drive tothe rocking lever and the blank feed mechanism.

At the extreme rear end of the mill, the input end, is the mandrel rodclamping mechanism 84 which is rigidly fastened to the rear wall ofhousing 68 by a heavy welded steel cantilever support 86.

Looking again at the front end of the mill as shown in FIG. 2, anintermediate blank clamp assembly 88 can be seen near the rear end ofthe rolling stand housing 66. The operating solenoid for theintermediate clamp is located in the box-like housing 90.

Near the left hand side of FIG. 1, a second drive motor 92 is securedunder the table on a support frame 94. Auxiliary motor 92 is used forspeeded up feed-in and return movement of the blank feed chuck 80.

Suitablylocated along the length of table 72, one or more welded steelstands 96 provide rigid support for the table, as necessary. Appropriatesheet metal cowling 98 can enclose the sides of the intermediate frameor table area. Blank pipe supports 100, which can be shifted andremoved, are used along the table to help support the mandrel spindleand blank, in a manner well-known in the pipe mill art.

Main and auxiliary mill control panels 102 and 104 are located on theside of the table near the rear and front ends and include variouselectrical control switches and indicator lights to operate and indicatemill condition.

The drive mechanism is bestunderstood with reference to- FIG. 3 withsupplemental reference to FIGS. 1 and 2. Drive power is derived from thetwo electric motors 54 and 92. The main motor 54 is a three-speedasynchronous electric motor which, with an electromagnetic brake 106, isinstalled on an adjustable base plate 108 (FIG. lb) for purposes ofadjusting the drive belt tension. A multiple sheave V-belt drive pulley110 and a brake drum 112 are installed on opposite ends of theelectricmotor shaft 114. Switching between desired ones of the three speeds ofthe electric motor speed is carried out, as required, by conventionalcontrol circuitry via one of the control panels 102 or 104. By providingvariable motor speed, greater versatility is enabled in cold rollingoperations, per mitting the: pipe mill to roll thin-wall pipes made froma number of different metals and alloys. 1

Drive power istransmitted from main motor 54 through driving pulley 110and multiple V-belts 116 to a large diameter multiple sheave drivenpulley 118 on an input shaft 120 to the reduction transmission 82. Oncethe mill is in normal operation, drive power for the rolling is throughthe input shaft 120 and within the reduction transmission is transferredvia gear 122 to a shifting gear cluster 124 (which is splined to atransfer shaft 126) thence via meshed speed reduction gears 128 and 130to a crankshaft 132. Secured on the end of crankshaft 132 is a crankwheel 134 carrying a crank pin 136 and connected between the crank pinand the rocking lever assembly 64 is a massive connecting rod 138 withits line of thrust being disposed under and in alignment with the pipefeed-in axis.

A second power output shaft 140 is connected to the crankshaft 132 via aset of bevel gears 141, 143 and projects rearwardly from the reductiontransmission 82 to provide primary drive power to the blank feeding andturning mechanism 70.

The crank mechanism 134, 136 furnishes the drive power to cause thereciprocal (see-saw) displacement of the rolling stand 62 by means ofthe. swinging lever assembly 64. Inside the reduction gear housing, apneumatic motor 142 connected to a shift lever 144 is used to shift thegear cluster 124 to mesh with driving gear 146 to furnish a special highspeed feed-in drive for moving an initial pipe blank up to the rollingstand.

Drive power for the blank feeding and rotating mechanism 70 isaccomplished by means of the main electric motor through its V-belttransmission, reduction gearing 82, and the transmission output shaft140 which is drive coupled to a long drive shaft 150 coupled at its rearend to an input shaft 152 for the blank feeding and turning mechanism70.

The mill rolling operation requires intermittent feeding and turning ofthe pipe blank, accurately correlated with a specific increment of therocking cycle of the rolling stand 62 (its extreme rear position). Thisaccurate correlation is enabled by means of a single geneva (MalteseCross") drive transfer assembly 154. Geneva drive derives from thecontinuously rotating input shaft 152 through gear 156, an idler gear158 and a gear 160 drive connected to the geneva drive input shaft 162.Shaft 162 carries and rotates the geneva crank 164. A six slot MalteseCross wheel 166, such as used in the present invention, is shown in FIG.4 and is subjected to periodic stepped rotation by the crank 164 throughits roller earn 168. When not being step driven by the crank the MalteseCross" is locked by a conventional locator or blocking plate 170. Crank164 and locator plate are continuously rotated at a number ofrevolutions per unit time equal to the number of double passes or cyclesof the rolling stand 62. When the rolling stand is approaching itsextreme rear position, the geneva crank roller cam 168 enters a slot ofthe cross 166 and rotates it one step, which with the six slot cross is60'? The rotation of the cross is terminated at the beginning of thestraight rolling pass of ther stand.

The geneva output. cross 166 is drive connected to a shaft 172, to whichis splined an axially fixed gear cluster 174 which provides a selectedone of two angular amounts of incremental rotation of the blank rotatingdrive shaft 176 (58l0' or 72) and also causes difi'erent numbers ofrotations of the feeding screw drive shaft 178. The gear cluster 174includes three gears 180, 182 and 184 which rotate as a unit and two ofthe gears, and 182, are used in conjunction with the shifting gearcluster 186 splined to turning shaft 176 to provide the two differentincrements of rotation (58l0' or 72), for reasons which will becomeapparent as the description proceeds. Gear cluster 186 is shifted by agear shift lever 188 (FIGS. 1a and 2a) on the top of the rear housing68.

The blank feed chuck drive is via a step up gearing from gear 184 of thegear cluster 174. Gear 184 meshes with a two gear idler cluster 190joumalled on the feed shaft 178, and

drive is transmitted through a shiftable gear cluster 192 splined totransfer shaft 194, thence through a second shiftable three gear cluster196, also splined to transfer shaft 194, to a selected one ofa threegear cluster 198, rotatably mounted on and operable to drive the feedscrew shaft 178 as will be' described hereinafter. The shiftable twogear cluster 192 is selectively meshed with one of the gears on cluster190 and the shiftable three gear cluster 196 is selectively meshed withan associated one of the gears on the cluster 198 by meansof the twogear shift levers 200 and 202 (FIGS. 1a and 2a) located on the side ofrear housing 68, providing six step-up gear ratios in the drive to thefeed screw drive shaft 178 during each cycle of rolling standreciprocation.

HIGH SPEED FEED SCREW OPERATION Under certain conditions, high speedcontinuous rotation of feed screw drive shaft 178 is desired, e.g.,feed-in of a pipe blank when the first blank is introduced at the startof mill operation and return of the floating chuck assembly 80 to itsrear start position when a succeeding pipe blank is fed into the mill.The auxiliary electric motor 92 with conventional reversing controls(not shown) furnishes the drive power for high speed feed shaftrotation. The auxiliary high speed power drive train is via theauxiliary motor shaft 204 which is drive connected through a brake 206(FIG. 1a) to an input shaft 208 joumalled in the rear mill housing 68.From input shaft 208 the auxiliary power is transmitted through a gear210 on the shaft 208 thence through an idler gear 212 to a frictionclutch input gear 214 rotatably joumalled on the feed screw drive shaft178 adjacent the feed shaft gear cluster 198. Located on and slidablysplined to feed screw shaft 178 is a shiftable coupling member 216. Oneface 218 of coupling 216 has jaw clutch teeth which, when the couplingis shifted to one position (normal speed), will positively mesh with thejaw clutch teeth on a clutch face member rigidly secured to the gearcluster 198. This condition enables feed screw drive derived from themain motor through the incremental geneva drive 154. The other face 222of coupling member 216 is a conical friction surface which can mate withan internal conical surface of a coupling face 224 on the clutch inputgear 214.

Coupling member 216 is selectively shifted from one to the other of thetwo positions by a shifting lever assembly 226 actuated by a pneumaticmotor 228 controlled by solenoid operated valves 230, in turn controlledthrough suitable control circuitry.

The ends of the blank turning shaft 176 project from the front and rearof the rear mill housing 68, being offset to one side from the axis ofthe pipe blank path, as seen in FIG. 2a, and it is aligned with and itsfront end is drive coupled with a long, blank turning shaft 240extending substantially the length of the mill. Shaft 240 is journallednear its rear end in a bearing block bracket 242 and at its front end ina bearing assembly on the intermediate blank clamp assembly 88. Thelong, blank turning shaft projects through the floating chuck assembly80 and is slidably drive coupled thereto.

The projected rear end of turning drive shaft 176 is coupled with analigned mandrel clamp turning shaft 244 enabling an incremental turningof the mandrel clamp (as well as the mandrel spindle) conjointly withturning of the blank.

The feed screw drive shaft 178 projects from the front side of the rearmill housing and is aligned and drive coupled with a long, feed screw246 extending substantially the length of the mill and disposed directlyunder the axis of the pipe blank feed path. The feed screw 246 isjoumalled against axial movement in tapered roller thrust bearingslocated in the rear bearing block bracket 242 and, at its front end, inthe intermediate blank clamp assembly 88. The feed screw 246,intermediate its front and rear journal portions, is threaded and isturned through a feed nut in the base of the floating chuck assembly 80,so that rotation of the feed screw 246 will feed the floating blankchuck assembly forward or backward.

In the cold rolling pipe mill operation being described, a mandrel head252 (FIG. made from steel and shaped to conform with the desired innerdiameter of the finished pipe is axially maintained in a predeterminedaxial position disposed within the rolling stand 62. A long mandrelspindle or rod 250 extends from the mandrel clamp assembly, whichsecurely clamps the rear end of the rod, along the feed path axis,through the floating blank chuck 80, along the length of the table 72,through the intermediate clamp 88 and into the rolling stand 62 where itcarries the mandrel head 252.

ROLLING STAND The rolling stand of the present invention, details ofwhich are shown in FIGS. 5-17, is an improvement over a prior art rollertype of rolling stand which has been used in the Soviet Union to rollthin-walled pipes. Most thin-walled pipes or tubes are produced by coldrolling on special Pilger mills which use rolls having complex workingpass grooves of changing profile or by multi-draft drawing over a shortor long mandrel. Tubes of 17 to 20 mm minimum diameter can be producedby a cold rolling process providing up to 75-80 percent reduction perpass. In West European countries it has been regarded inexpedient toroll tubes with wall thicknesses less than 1 mm.

The improvement of the working tool calibration pattern enabled theSoviet Union to efi'ectively roll tubes having walls down to 0.6 mmthick on the Pilger roll-type (called so as to be distinguished from theroller-type mills). Any further reduction in the wall thickness of tubesrolled on the roll-type mills involves great difficulties resulting fromexcessive elastic contact compression of the working tool with rolldiameters specified. As a result, specific roll forces are increasedwhich lead to a much greater degree of sticking of metal particles tothe working tool and resultant deterioration of the quality of thefinished tubes surface. The reduction of roll diameters in such priorart mills has been limited by the load-carrying capacity of the rollbearings. The complexity involved in accurately machine working thepasses of changing profile also makes it difiicult if not impossible, toobtain thinner walled tubes on the Pilger roll-type mill due toincreased likelihood of transverse non-uniformity of the wall thickness.

In the development of new mills (of which the present is an improvedversion) for rolling super thin-walled tubes (tubes with wallthicknesses less than 0.02 of the outside diameter), instead of usingtwo complex changing profile former surfaces in large diameter workrolls of the Pilger roll-type tube mill, three or more small diameterrollers are employed, these rollers having grooves of constant profilenot changing around the circumference, and either use no axle or useshort integral rolling shanks whose diameter approaches that of thebottom of the working groove.

Instead of using back-up rolls as used in some cluster mills,special-type contoured tracks on straps or gibs support the cylindricalstub shank journals of the work rollers. The profile of the strap trackprovide the amount of reduction movement by the rollers and therefore,function both as bearings and formers for the work rollers. The strapsor gibs are mounted in a thick-walled tube of the mill rolling standcarriage, which is reciprocated by the crank-and-link drive of the mill.

The work rollers, held against the straps, are mounted in a separator.With the mill running idle, the separator is moved by a kinematic leversystem inside the working carriage at a speed corresponding to thevelocity of the rollers as they roll along the tube axis during therolling process to synchronize the location of the rollers in therolling head.

Referring initially to FIGS. 5-8, the rolling stand 62, followed bydetails of the rocking lever assembly 64, will now be described. Therolling stand is of primary importance to successful mill operation andincludes a heavy, rigid roller head 680 secured in a carriage 682, thecarriage serving as a crosshead and including a yoke post 684 to which aconnecting rod 686 from the rocking lever assembly 64 is connected.

The rolling stand carriage 682 is fabricated from rigid steel plate andits frame consists of two flat side beams 688 and 690, a rear wall 692and a front wall 694 welded as at 696 and 698 (as shown in FIGS. 7 and8) to respective areas of the side walls. The rear wall is locatedapproximately at the mid point of the side walls. Both the rear wall 692and the front wall 694 have circular openings 700 and 702, respectively,which are aligned and releasably receive and mount the rolling head 680.Immediately adjacent the upper front side of rear wall 692 an arcuatesaddle 704, made from steel plate, is welded to the rear wall and upperedges of the two side plates 688 and 690. The inner surface of saddle704 is coextensive and coaxial with the upper periphery of the circularopenings 700 and 702. Tire hereinbefore described joke post 684 iswelded to the top center of saddle 704 and to the top edge of rear wall692 and, with the saddle, constitutes the drive yoke by which thecarriage is reciprocated through its double passes.

The rolling stand carriage 682 is installed in the mill on eight rollers706-713, roller bearing mounted on stub axles (see FIG. 8) fixed in eachcorner of the outer side of the two side plates 688 and 690. The rollersroll along the top and bottom surfaces of two horizontal steel bartracks 718 and 720 (FIGS. 7 and 8) which are fastened to the rigidsupport framework of the front mill housing 66, preferably by machinescrews. Tracks 718 and 720 are parallel to the mill feed path axis andaccurately guide the reciprocation of the rolling stand 62. The fourupper rollers support the weight of the rolling stand and the four lowerrollers prevent pitching of the stand during operation. Horizontal foreand aft grooves 722 and 724 in the outer surfaces of respective sideplates 688 and 690 carry six anti-friction gibs 726, made from bearingbronze, which provide a close sliding fit against the opposing faces ofthe two horizontal tracks 718 and 720 and prevent yaw, or cocking of therolling stand sideways, during operation.

The rolling head assembly 680 includes a thick walled cylinder 730,which carries the rollers, a roller separator,

roller strap tracks or gibs and track adjustment mechanism, and isremovably inserted into the carriage through its front wall opening 702.The cylindrical outer surface of the head 680 has a close fit throughthe front and rear walls of the carriage and is maintained againstrotation relative to the carriage by a key 732 and cooperating key waysin the head and at the bottom of the rear wall 692. A peripheral outerflange 734 at the front end (right hand side of FIG. 6) of the headcylinder 730 abuts against the front carriage wall 694 to limitinsertion of the head and axially locates the head in the carriage. Anarcuate cross bar 736 placed in an arcuate groove 738 across the top ofcylinder 730, and fastened by screws 740 to the rear of carriage frontwall 694, rigidly locks the head to the carriage.

Fixed by screws at equi-angular locations on the inside surface ofcylinder 730 are three slideways 742, seen in FIGS. 6 and 9, each ofwhich has an inwardly facing, axially disposed channel track 744. Aslide or carrier 746, made from a steel block, having a somewhattriangular cross-section, has three outwardly facing slide bosses 748. Fastened by screws to each slide boss 748 is a channel shaped, bearingbronze, gib 750, which enable the slide to slidably fit the channeltracks 744 of the slideways 742, and maintain the slide 746non-rotatable relative to the head yet permit an axially slidablerelationship. An axial through bore 752 in slide 746 is dimensioned toprovide passage with a free fit for a pipe blank. Extending back fromthe rear end of slide 746 at the sides ofthe bore are two integral,laterally spaced apart arms, 754 and 756, with aligned lateral crossbores in their ends. Connected to each of the arms 754 and 756 byindividual axle pins 758 is the forked end 760, 762, of an individualslide operating connecting rod, 764 and 766, respectively. The otherends of the two rods 764 and 766 are connected to the rocking leverassembly, as will be described, hereinafter.

Coextensive with the slide 746 and secured by nuts and studs 768 to itsfront end is the body 770 of a unit termed a separator, which keeps theworking rollers in proper position in the head when they are notactually performing a rolling operation. The separator body 770, shownindetail in FIG. 10, is essentially triangularly shaped in cross section(see FIG. 8), has a large concentric, axially disposed through bore 772and axially disposed stud bores 774, in each of the arms through whichthe fastening studs 768 project. Intermediate its two ends and betweenits three arms the body 770 has three recesses or windows 776 disposed 120" apart. The ends and sides of each window are accurately shaped toradially receive a working roller 778 and front and rear roller shankbearing inserts 780 and 782. The inserts are channelled to freely bridgethe center'working groove portion 783 of rollers 778 with their flangesshaped with arcuate surfaces to rotatably fit the two shanks 784 of theassociated roller.

Two hard steel cylindrical inserts 786 and 788 are inserted I inrespective front and rear ends of the coaxial through bore 772 and thenare welded to the separator body 770. The inner ends of body cylindricalinserts project slightly into the roller working space formed by theintersection of the three windows 776 and are cut away as at 790 and792, under the ends of each window, as an extension of the bearinginsert walls. The bottom of each bearing insert 780 and 782 has arecessed spring pocket 794 and 796, respectively, which seats a small,coiled compression spring, 798 and 800, respectively. Each workingroller 778 with a set of two bearing inserts 780 and 782 and theirrespective balancing springs 798 and 800 are radially inserted into eachof the separator windows 776.

The inserts slidably fit the walls of their windows and in turn hold theworking roller by their cylindrical shanks. The inserts with the rollersare prevented from moving radially out from within the window by aspecial locking plate 802 secured by a screw to the separator body 770.The two balancing springs 798 and 800 seat on the cutout flats 790 andresiliently bias their inserts and retained roller 778 outwardly to thelimit position dictated by the lock plate 802.

During the rolling operation the working rollers 778 are supported (bymeans of their shanks 784) and roll on the contour surfaces of thesupport planks or straps 810, as will be hereinafter described. Thespring balancing of each working roller 778 considerably softens theirworking conditions during the moment of pipe blank feeding and rotatingwhich occurs at the beginning of the rolling process. The springbalancing also provides gradual speed increase after reversal of thestand into its forward pass and prevents slippage of the roller shanks784 along the support planks 810, as well as eliminating lashing of thepipe by the rollers during the clamping moment (grabbing).

Balancing of the working rollers is also necessary during the rolling ofthe forward end of the pipe onto the mandrel.

The two cylindrical front and rear inserts 786 and 788 have insidediameters permitting free passage of a pipe blank. A threaded end 804 ofthe front insert 786 projects beyond the front face of the separator 770and receives spacing washers and gaskets 806 secured by a nut 808. Thestuds 768 project through the washers and gaskets 806 and the nutsscrewed on the studs transfer clamping force through the washers to theface of the separator body 770 to fasten it securely on the slide 746.Thus the separator with the working rollers will reciprocate as a unitwith the slide.

The perspective view of FIG. 13 clearly illustrates how three workingrollers and their track strap groupings are arranged. The straps 810 arehard steel channels, with upper edges 812 and 814 of the flangescarefully contoured to provide inclined roller track formers. The bottom816 of each strap as shown in FIG. 14, is flat but inclined up in adirection toward the front end of the strap. FIG. 14 is a distorted viewshowing the track edge contour 812 substantially exaggerated forillustration. The actual contour change is quite small. The grooveworking surface 783 of the roller rides with a sliding fit between thestrap flanges while the large diameter stub shanks 784 take the rollingload, bearing on and rolling along the contoured edges 812 and 814 ofthe strap flanges during the fore and aft passes of the roll stand. I I

Returning to FIGS. 6 and 9, the side faces 818, of fixed slideways 742are spaced from and are parallel with adjacent slideway side faces 818to constitute three guideways for the three roller track straps 810,each of which is disposed in a guideway between adjacent faces 818 ofthe slideway 742 fitting with a snug sliding fit against an abutmentpart 820 of a rear cover plate 822 fastened on the thick-walled cylinderbody 730 by screws. An inner front housing cover plate 824 is held onthe front of the cylindrical body 730 by screws and provides a frontretaining abutment for axially holding the straps against the rearabutments with a snug but sliding fit.

Under each strap 810 is a flat wedge shaped adjusting gib 826 extendingthe length of the strap and having an inclined face which matches andengages the bottom inclined surface 816 of the associated strip 810. Thefront end of each wedge gib 826 is fastened to a common ring 828 whichin turn is fastened by screws to a bushing ring 830 which has screwthreads 832 on its outer periphery. A ring gear 834 with screw threads836 on its inner periphery is threaded on the screw threads 832 of thebushing ring 830 and journalled adjacent the front end of cylindricalbody 730 by two ring bushings 838 and 840 held in place by a gear cover842. At the top of the housing and meshed with the ring gear 834 is asmall pinion gear 834 keyed on an operating shaft 846 joumalled inbushings mounted in the top walls of the gear cover 842. The pinionshaft 846 projects through to the front of gear cover 842 and securedthereto is a hand wheel 848. Rotation of wheel 848 will rotate the ringgear 834 and, via its threaded connection with ring bushing 830, willshift the wedge gibs forward or backward to adjust the strap tracks 810radially inward or outward. The screw thread connection between ringgear 834 and ring bushing 830 constitutes an irreversible connection sothat once a wedge adjustment is made by the hand wheel, it isself-maintaining, although a locking pin 849 can be provided to engagethe pinion teeth. The purpose of adjusting the radial disposition oftrack straps 810 is described in a following section of thisdescription.

Track straps 810 are held outwardly against the wedge gibs 826 by springloaded studs 850 projecting through free fitting apertures in thecylinder body 730, slotted apertures 852 in the wedge gibs 826 andscrewed into a threaded hole 854 (FIG. 13) in the bottom of a trackstrap 810. A cupped washer 856 and a coil spring 858 are held over theouter end of each stud by a nut with the washer and spring recessed intothe wall of the cylinder body 730 and provide the bias force on thetrack straps 810.

ROCKING LEVER ASSEMBLY The rocking lever assembly 64 is actually twospaced apart heavy levers 870 and 872 (FIG. 7) assembled on a rock shaft874 intermediate the lever ends. Each lever has a collar 876 welded toits side face at the rocking axis and with a spacer sleeve 878 betweenthe collars are fixed on shaft 874 by suitable set screws. The ends ofrocking shaft 874 project beyond the outer sides of each lever and arejournalled in roller bearing sets 880 secured in pillow blocks 882bolted to heavy angle brackets 884 and 886 fixed to the rigid internalframe of the roller stand housing 66.

The lower ends of the spaced levers 870 and 872 constitute a forkcoupling into which fits the front end of the aforedescribed connectingrod 138 (FIG. 1b). A connecting pin 888, placed through apertures in thelower ends of the levers and the front end of connecting rod 138 couplethe rod and lever. Lock plates 890, fastened by screws hold the pin 888in position and a grease fitting 892 is included in the connecting pin888. The lower ends of levers 870 and 872 are reinforced by a brace rod894 and spacer sleeve 896.

The spaced apart upper arms 898 and 900 extend up on either side of thepipe blank feed path axis with their ends located above the top of thefront mill housing 66. The upper lever ends are apertured and receivecollared bushings 902 and 904 which journal the stub axles 906 and 908of a trunnion 910. The rear threaded end 912 of the roll standconnecting rod 686 passes through the trunnion body and is clamped bytwo lock nuts 914 and 916 enabling adjustments to the operating lengthof the rod 686.

A fork fitting 918 on the front end of roll stand connecting rod 686connects to an adjustable axle 920 held in a shiftable dummy block 922slidable up and down in a canted guideway 924 in the roller carriageyoke post 684. An upstanding stud 926 connects to and is pinned to thedummy block 922 and projects through a screw sleeve 928 threaded downthrough the top of yoke post 684 and abutting the dummy block 922. Theupper end of stud 926 is threaded and receives a lock nut 930. A secondlock nut 932 on the sleeve nut enables locking its adjustment. The dummyblock 922 can be shifted by loosening the two lock nuts and adjustingthe sleeve nut 928 for purposes to be hereinafter explained.

Between the rocking shaft 874 and the ends of both of the upper leverarms 898 and 900, the arms are slotted at 934 and 936 and receive slideblock bushings on the ends of axle pins 938 and 940 which projectinwardly and journal the respective ends of the two separator slideconnecting rods 764 and 766, via suitable bushings. The facing ends ofthe two axle pins 938 and 940 pass through apertures in the arms of anadjusting yoke 942 (which bridges the pipe blanks feeding into therolling stand) and are secured to the arms by nuts 944. The threadedstem 946 of yoke 942 projects up through a hole 948 in a rigid crossbrace 950 secured between the two upper lever arms. By manipulating thetwo lock nuts 952 and 954 on the threaded yoke stem 946 the yoke 942 canbe adjusted up or down in the lever slots 934 and 936, in conjunctionwith adjustment of the roll stand dummy block 922, for purposes as willbe explained.

Shown in FIG. 5, an indicator pointer 956 is secured on the end of yokeaxle 940 to enable predetermined adjustments of the yoke 942. A similaradjustment indicator 958 is included on the outside of the rolling standdummy block 922.

FIG. 1 1 is a representation of the manner in which three rollers 778with stub axle shanks 784 are disposed to roll along three channel typetrack straps 810 in a heavy cylindrical head 730, with the rollerperipheries rolling against the outer surface of a pipe blank 966 fittedover the mandrel head 252. FIG. 12 is a similar representation showing afive roller embodiment wherein the track formers are bars 970 contouredto fit the groove peripheries of the working rollers 972. in the fiveroller embodiment the rollers are too close together to enable use ofthe large diameter axle shanks. The five roller head 730' contains allcomponents such as slideways, separator, and wedge gibs as have beendescribed for the roller head 730, the components difiering somewhat instructural shape to accommodate the bar tracks 970 and rollers 972without shanks.

Although the aforeidentified article from Metalurgizdat 1966 describesthe precise technique of making the roller track contours, adiagrammatic strap track 810 is shown in FIG. 15. If the roll stand passis 450 mm, the straps 810 are shifted 450 mm and the rollers roll thatdistance along the tracks and essentially half that distance along thepipe blank, thus the track contours must be long enough to accommodatethe 450 mm roller travel and the mandrel head is disposed at least thelength of the roller travel along the pipe blank.

The work surface of the support track 812 (FIG. 14) consists of thefollowing segments: A-the roller opening at the pipe feeding androtating position; B--reduction segment (compression); C--reductionsegment; and Dcalibrating segment.

The purpose of each of these segments is analogous to the purpose ofcorresponding segments of a pass groove of cold rolling pipe mills ofthe roll type.

The decrease of the pipe blank diameter to a finished pipe diameterduring the cold rolling on the thin-wall mills is quite small, due tothe fact that the radius of the pass groove which is constant along theperimeter of the roller is equal to the radius of the finished pipe. Inthe case of considerable difference between the diameter of the blankand the finished pipes the rollers will cut into the blank. This leadsto the intensive flow of metal into the spaces between the rollers andto the spoiling of the pipe surface. During the comparatively smallreduction of the pipe during the rolling process the clearance betweenthe inner surface of the blank and the mandrel usually does not exceed1.0-1.5 mm. Therefore, the length of the reduction segment B can beselected within the 10-12 mm limit.

The contour of the track segment A, corresponding to the blank feedingand pipe rotation jaw opening, must guarantee impossibility of contactof the rollers with the pipe blank during the feeding and rotationoperations.

ROLLING STAND OPERATION The cold rolling mill rolling stand 62 works onreciprocating motion principle. The rolling of the pipes is carried outon a stationary cylindrical mandrel head 252 with the help of three ormore (depending on the adopted scheme) working rollers 778. At the endof a straight forward pass of the stand 62 the rollers 778 have beenmoved together to form a closed round groove in cross section,essentially as seen in FIG. 11.

The working rollers are supported by large diameter shanks 784 or,alternatively their work surface (groove surface), by means of contouredtracks such as 810 which provide the regulation of the ring spacebetween the roller groove and mandrel 252 along the work pass of thestand. The ring groove formed by the three rollers at the beginning ofthe work pass of the stand is larger than it is at the end of the pass.

The roll stand 62 consists of the thick walled sleeve 730 inside whichare installed three or more support tracks 810 along which the workingrollers 778 roll. Synchronism of the longitudinal displacement of therollers is provided by a separator 770 fastened to the slide block 746.The position of the slide block 746 in relation to the sleeve 730 isfixed by the yoke 942. The rolls with the separator, support tracks, andthick-walled sleeve are installed in the welded carriage 682 of the rollstand, and can be quickly and simply removed and replaced with minimumefiort. The roll stand is connected with the crank and reductionmechanism 82 by rocking lever assembly 64 which imparts the reciprocalmotion to the stand.

During the movement of the rocking lever assembly which, as has beenhereinbefore described, is connected to both the thick-walled roll standhead 730 and to the separator by a parallel connecting rod arrangement,the operating force is transmitted to the thick-walled head 730 by theheavy connecting-rod 686, the slide 746 being merely reciprocated insynchronization to maintain the rollers in proper axial disposition atthe beginning of the pass. The length of the separator travel is theactual working pass of the rollers and is determined by the position ofthe connecting rods 764 in connections to the rocking lever in relationto the rocking axis of the rocking lever. This position can be changedby means of the adjustable yoke 942.

Taking into account the operation conditions, the slide connecting rods764 must be parallel to the head connecting rod 686 during carriagereciprocation. If the lock position of the slide connecting rods 764 ischanged, the parallelism is disturbed. The parallelism is re-establishedby regulation of the length or connection point of the head connectingrod 686. The two points of attachment of the separator slide connectingrod and that of the carriage to the rocking lever are situated in such away that the linear speed of the roller separator and the magnitude ofits displacement along the rolling axis is approximately twice as smallas that of the carrlage.

In order to compensate for the elastic deformation of the workinginstruments (tools) and the cylindrical head, the possible inaccuraciesin the manufacture of the instruments, and the adjustment of the mill,the special wedge gibs 826, provided with adjustment via the hand wheel848, enable regulation of the strap track height.

During the development of the separator (retainer) and the strap tracksthe possibility of insignificant displacement of the rolls along theworking surfaces of the support tracks in the transverse direction wasincorporated. This allows the self-adjustment of the rollers along therolled pipe and decreases considerably the unevenness of the deformationalong the perimeter of the pipe, thus improving its quality.

The spring balancing of the roll stand rollers considerably softenstheir operation conditions during the moment of feeding and rotation ofthe blank and at the beginning of the rolling. The balancing provides agradual increase in roller rotation speed after the carriage has beenreversed, precludes the slippage of the shanks along the support tracks,and at point of impact of the rollers on the pipe during the seizuremoment.

The components of the mill are quite simple in form and are simple tomanufacture. The work profile of the strap support tracks are acombination of sloping planes. The groove of the roll corresponds to thesize of the finished pipe and is maintained along the entire perimeterof the roller. When switching from the rolling of pipes of one diameterto the rolling of pipes of another diameter the rollers and mandrel arechanged and the lever system of the carriage is readjusted.

In the exemplary machine the following conditions exist keeping in mindthat the main motor is a three speed electric motor.

1. Transmission ratio number from motor to the crank gear l 2.Transmission ratio from the motor to 7. Number of revolutions 715, 960,1430 rpm 8. Number of double passes of the Rolling 140/95/70 pass/min.

Stand 9. Length of the Rolling Stand pass 450 mm.

ROLLING MILL OPERATION In the exemplary mill, loading of the pipe blanksis carried out manually. During the work process the mill can beoperated by one operator and allows the rolling of measured blanks 4meters in length as well as unmeasured ones less than 4 meters inlength.

A rod 250 with a required diameter and length of mandrel head 252 isplaced into the mill. The blank feeding chuck is placed into extremerear position.

The feed chuck is opened and the coupling of the feeding and rotatingmechanism is placed into working position. The mandrel rod clamp 84 isjust closed manually on the mandrel rod end grooves to locate themandrel and then the electromagnetic blank clamp 88 is closed on thefront part of the mandrel through a terminal switch and electricsolenoid 642. The mandrel clamp is then opened.

The pipe blank, coated internally with a lubricant emulsion, is pushedover the mandrel through the mandrel end clamp and into the sectorbetween the mandrel end clamp and intermediate blank clamp, after whichthe mandrel rod end clamp is closed manually. When that is done, via itsterminal switch 410, which is actuated by closing the mandrel rod endclamp, the electromagnetic intermediate blank clamp 88 opensautomatically.

The pipe blank is next manually clamped in the lathe type feeding chuckhead. When rolling pipes with a rigid chuck the angle regulating handleon the feeding and turning mechanism is placed into positioncorresponding to the blank rotation angle of 5810 andwhen rolling isdone with floating chuck the handle is placed into positioncorresponding to the angle of rotation of 72. The necessary blankfeeding value is chosen by shifting of the feeding speed shift handles.

Due to technological reasons, the start of rolling of the forward end ofthe first blank is carried out at a fast feed-in speed.

The feeding and turning operations are actually a combined operationperformed when the working carriage is in its extreme rear position andthe work rollers are set apart at a maximum distance from the axis ofthe tube rolled.

Viewing FIG. 15, upon start of the forward travel of the carriage andcontoured track 810, a part of the tubular pipe blank stock 966 whichhas already been fed is gripped by the work rollers 778. Being broughttogether radially, the rollers float" in the'direction of the carriagemovement, and periodically reducing this part of the stock, they roll itover a cylindrical mandrel 252 to the desired diameter and wallthickness. During the return stroke of the carriage, some reduction ofthe part of the tube still on the mandrel head also takes place owing toelastic compression of the working tool-working carriage system.

For purposes of visual demonstration, the kinematics of the process oftube rolling by rollers may be compared to rolling a pencil held down bya palm over a table, the palm moving in the longitudinal direction. Inthis case the palm will correspond to the thick-walled tube of theworking carriage accommodating the shaped track straps; the pencil, tothe work rollers; and the table surface, to a tube being rolled on astationary mandrel.

The advantage of the process of tube rolling by rollers are as follows:

a. Small diameter of work rollers and corresponding reduc-. tion in thespecific roll force and in the contact surface between the metal, theroller and the mandrel.

b. Some decrease in elastic compression of the rollers and the mandreland the possibility for producing tubes with much thinner walls.

c. It is possible to roll tubes of much smaller diameters as compared tothe Pilger roll-type mills.

d. The working tool may be manufactured with an accuracy of 10.01 mm.

e. There are no expensive roll bearings having low service life.

f. Sliding of the roller pass surfaces over the tube rolled is sharplyreduced owing to a greater number of rollers and the constantcrossdsection of their grooves.

g. Metal sticking to the working tool is minimized due to some reductionin the specific roll force and sliding.

h. Self-aligning of the rollers over the tube which minimizes thepossibility of rolling marks formation on the tube.

i. It is possible to roll the so-called non-scratched" tubes, havingoutside and inside surfaces of high quality finish, which, apart fromall other factors involved, is aided by the use of a cylindrical mandrelrotated synchronously with the tube being rolled.

As shown in FIG. 16, the peripheries of a roller for a three rollerstand are beveled at their edges on angles of 120 so that the threerollers will meet and mate with a true ring cross section when theyreach the finishing segment of the tracks. The bevel angle limits thepermissible shank width and diameter. in rolling out of the rollers, thesharp bevel R is rolled ofi' until the angle of the tangent to theperipheral edge zone of the profile groove rolling zone of the roller issmaller than the normal 60 angle normally formed by a sharp bevel edge.The amount of necessary rolling out of such roller edges depends uponthe amount of diametral reduction between the pipe blank and that of thefinished pipe. The chart shown in FIG. 17 provides the correct rollingout angle for the diametral reduction.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent 1. A pipemill reducing roll stand adapted to reciprocate along opposed, spacedapart tracks, disposed parallel to a pipe blank feed path axis, saidroll stand comprising: a carriage with hearing means adapted to engagethe tracks and reciprocally mount said stand on the tracks; a thickwalled roller mounting head rigidly fastened in said carriage coaxialwith the feed path axis; a roller separator slidably mounted within saidhead for reciprocation along said feed path axis relative to said head;working rollers in said separator spaced at equi-angular locationsaround said axis; means resiliently mounting each of said workingrollers for limited radial shift in said separator comprising bearinginserts with surfaces embracing cylindrical surfaces on said workingroller, first guide means in said separator, second guide means on saidbearing inserts cooperating with said first guide means to confine saidbearing inserts and associated roller as a unit and permit radialreciprocation of said unit between limit positions, coil springsdisposed between said bearing inserts and said separator biasing saidunit radially outward, and abutment means on said separator defining thelimit positions of said unit; and means on said carriage enablingattachment of reciprocable drive means.

2. A pipe mill roll stand, as defined in claim 1, wherein said insertshave spring seat recesses facing the center of said separator, saidsprings are small compression coil springs seated in associated ones ofsaid recesses, and said abutment means include abutment portions on theinterior of said separator, spaced radially from its axis, to providethe other seating surfaces for said springs.

3. A pipe mill roll stand, as defined in claim 2, wherein said rollershave a groove working profile which is constant along the rollerperimeter and cylindrical journals on each side of said working groove;each bearing insert in a block with two legs, contoured to bear on thetwo shanks, bridging the working profile; two of said blocks and anembraced roller slide radially in a window provided in said separator;and a removable lock plate on the outer side of said separator overlaysthe window and retains said inserts and associated roller within saidseparator.

4. A pipe mill roll stand, as defined in claim 1, wherein said carriagehas a frame construction with two apertured end walls; said roll head isa thick-walled cylinder which is inserted through the apertures in bothof said end walls; removable means, secured to at least one of said endwalls, cooperate with said cylinder to rigidly maintain said cylinder inaccurate angular and axial disposition in said carriage and permit rapidremoval and replacement.

5. A pipe mill roll stand, as defined in claim 4, wherein said carriageframe has side members; and said means enabling attachment of the powermeans comprises a saddle rigidly fastened to said side members and saidone wall, and an upstanding post rigidly secured to said saddle and saidone wall; and means in said post enable an adjustable connection to anend of a connecting rod, permitting shifting of said connection towardand away from said saddle.

6. A pipe mill roll stand, as defined in claim 5, wherein said drivemeans has parallel linkage means, including said connecting rod and linkmeans connected to said separator, whereby reciprocable shifting of saiddrive means provides synchronized shifting of the thick-walledcylindrical head and of the roll separator at different rates.

7. A pipe mill roll stand, as defined in claim 6, wherein said headincludes contoured working roller track gibs secured in said headagainst axial and angular shift and along which said floating workingrollers roll during reciprocation of said head.

8. A pipe mill roll stand, as defined in claim 7 wherein meansresiliently secure and bias said track gibs to the inside of the wall ofsaid head, wedge means are disposed between each track gib and the headcylinder wall so that fore and aft shifting of said wedge means canchange the radial disposition of said track gibs relative to the axis ofsaid head cylinder; adjustment means on the front end of said head areattached to said wedge means to enable simultaneous adjustment shiftingof all said wedge means.

9. A pipe mill roll stand, as defined in claim 8, wherein said wedgeadjustment means includes: an axially shiftable ring bushing in thefront end of said head connected to each said wedge means, said bushinghaving screw threads on its outer periphery; a ring gear with internalscrew threads engaged with the screw threads on said bushing andjournalled in the front end of said head against axial shift; and a ringgear operator including a spur gear joumalled in said end of said headand meshed with said ring gear.

10. A pipe mill support means and reducing roll stand reciprocablycarried on said support means which includes opposed, spaced aparttracks, disposed parallel to a pipe blank feed path axis; said rollstand comprising a carriage with bearing means adapted to engage thetracks and reciprocally mount said stand on the tracks, a thick walledroller mounting head rigidly fastened in said carriage coaxial with thefeed path axis, a roller separator slidably mounted within said head forreciprocation along said feed path axis relative to said head, workingrollers in said separator spaced at equi-angular locations around saidaxis, and means on said carriage enabling attachment of reciprocableconnecting rod means; a vertical rocking lever disposed in said supportmeans adjacent the rear end of said roll stand with its rocking axisbelow the feed path axis and an upper arm projecting to an end connector located above the feed path axis; connecting rod means connectedbetween said upper lever arm and said roll stand.

11. A pipe mill support and roll stand, as defined in claim 10, whereinsaid carriage has a frame construction with two apertured end walls;said roller head is a thick-walled cylinder which is inserted throughthe apertures in both of said end walls; removable means, secured to atleast one of said end walls, cooperate with said cylinder to rigidlymaintain said cylinder in accurate angular and axial disposition in saidcarriage and permit rapid removal and replacement.

12. A pipe mill support and roll stand, as defined in claim 11, whereinsaid carriage frame has side members; and said means enabling attachmentof the connecting rod means comprises: a saddle rigidly fastened to saidside members and said one wall, and an upstanding post rigidly securedto said saddle and said one wall; and means in said post enable anadjustable connection to an end of a connecting rod, permitting shiftingof said connection toward and away from said saddle.

13. A pipe mill support and roll stand, as defined in claim 12, whereinsaid connecting rod means has parallel linkage means, including saidconnecting rod and link means connected to said separator, wherebyrocking of said lever provides synchronized shifting of the head and ofthe separator at different rates.

14. A pipe mill support means and roll stand as defined in claim 10,wherein said connecting rod means includes link means connected betweensaid end connector and said carriage, and adjustable link meansconnected between said upper arm means and said separator.

15. A pipe mill support and roll stand as defined in claim 14, whereinsaid link means between said end connector and said carriage has anadjustment device at the connection to the upper lever arm and a secondadjustment device at the connection to the carriage.

16. A pipe mill support means and roll stand as defined in claim 10,wherein said rocking lever means has upper and lower lever arms and itsrocking axis is located intermediate the ends of said upper and lowerlever arms and the end of said lower lever arm provides means forconnection to a reciprocating power drive means.

17. A pipe mill support means and roll stand as defined in claim 16,wherein said lever means includes at least two laterally spaced apartelongate members extended upwardly in balanced disposition on each sideof the feed path axis and the lower portions of said elongate membersconstitutes a forked lower lever arm and include said means providingfor a connection to a reciprocating power drive means.

18. A pipe mill support and roll stand as defined in claim 10, whereinthe top portion of said roll stand includes attachment means providingdrive transfer connection between said carriage and at least a portionof said connecting rod means.

19. A pipe mill support and roll stand as defined in claim 18, whereinsaid carriage comprises frame structure and said attachment means is anupstanding connector link rigidly secured on top of said framestructure.

20. A pipe mill support means and reducing roll stand as defined inclaim 10, wherein said roll stand includes means mounting each of saidworking rollers for limited radial shift in said separator comprisingbearing inserts with surfaces embracing cylindrical surfaces on saidassociated working roller, first guide means in said separator, secondguide means on said bearing inserts cooperating with said first guidemeans to confine said bearing inserts and associated roller as a unitand permit radial reciprocation of said unit between limit positions.

21. A pipe mill support means and reducing roll stand reciprocablycarried on said support means which includes opposed, spaced aparttracks, disposed parallel to a pipe blank feed path axis; said rollstand comprising a carriage with bearing means adapted to engage thetracks and reciprocally mount said stand on the tracks, a thick walledroller mounting head rigidly fastened in said carriage coaxial with thefeed path axis, a roller separator slidably mounted within said head forreciprocation along said feed path axis relative to said head, workingrollers in said separator spaced at equi-angular locations around saidaxis, and means on said carriage enabling attachment of reciprocableconnecting rod means; a vertical rocking lever means disposed in saidsupport means adjacent the rear end of said roll stand with its rockingaxis below the feed path axis and an upper lever arm means withconnection means located between the feed path axis; and connecting rodmeans-connected between said upper lever arm connection means and saidroll stand, including adjustable link means connected to said carriage.

22. A pipe mill support and roll stand as defined in claim 21, whereinsaid adjustable link means has a first adjustment device at theconnection to the upper lever arm and a second adjustment device at theconnection to the carriage.

23. A pipe mill support means and roll stand as defined in claim 21,wherein said connecting rod means includes a second adjustable linkmeans connected between said upper lever arm means and said separator.

24. A pipe mill support and roll stand, as defined in claim 21, whereinsaid carriage has a frame construction with two apertured end walls;said thick-walled roller mounting head is inserted through the aperturesin both of said end walls; means, secured to at least one of said endwalls, cooperate with said roller mounting head to rigidly maintain saidhead in accurate angular and axial disposition in said carriage andpermit rapid removal and replacement.

25. A pipe mill support and roll stand, as defined in claim 24, whereinsaid carriage frame has side members; and said means enabling attachmentof the connecting rod means comprises: a saddle rigidly fastened to saidcarriage frame and an upstanding post rigidly secured to said saddle anda said end wall; and said adjustable link means includes connectingmeans in said post enabling an adjustable connection permitting shiftingof said connection toward and away from said saddle.

26. A pipe mill support and roll stand, as defined in claim 21, whereinsaid connecting rod means has parallel linkage means, including saidadjustable link means and link means connected to said separator,whereby rocking of said lever provides synchronized shifting of the headand of the separator at different rates.

27. A pipe mill support and roll stand as defined in claim 21, whereinthe top portion of said roll stand includes attachment means providingdrive'transfer connection between said carriage and said adjustable linkmeans.

28. A pipe mill support and roll stand as defined in claim 27, whereinsaid carriage includes frame structure and said attachment meansincludes an upstanding connector link rigidly secured on top of saidframe structure, said attachment means further including apivot'connection portion adjustably shiftable toward and away from saidcarriage in said upstanding link.

29. A pipe mill reducing roll stand adapted to reciprocate alongopposed, spaced apart tracks, disposed parallel to a pipe blank feedpath axis, said roll stand comprising: a carriage with bearing meansadapted to engage the tracks and reciprocally mount said stand on thetracks; a thick walled roller mounting head rigidly fastened in saidcarriage coaxial with the feed path axis; a roller separator slidablymounted within said head for reciprocation along said feed path axisrelative to' said head; working rollers in said separator spaced atequi-angular locations around said axis; means mounting each of saidworking rollers for limited radial shift in said separator comprisingbearing inserts with surfaces embracing cylindrical surfaces on saidworking roller, first guide means in said separator, second guide meanson said bearing inserts cooperating with said first guide means toconfine said bearing inserts and associated roller as a unit and permitradial reciprocation of said unit between limit positions; and means onthe top portion of said roll stand carriage enabling attachment of drivemeans for reciprocation of said carriage.

30. A pipe mill reducing roll stand as defined in claim 29, wherein saidmeans on the top portion of said carriage includes an upstandingconnector link rigidly secured on top of said carriage and a pivotconnection portion adjustably shiftable toward and away from saidcarriage in said upstanding link.

31. A pipe mill reducing roll stand, as defined in claim 29, whereinsaid carriage has a frame construction with two apertured end walls;said roller mounting head is a thick-walled cylinder which is insertedthrough the apertures in both of said end walls; removable means,secured to at least one of said end walls, cooperate with said cylinderto rigidly maintain said cylinder in accurate angular and axialdisposition in said carriage and permit rapid removal and replacement.

32, A pipe mill roll stand, as defined in claim 31, wherein saidcarriage frame has side members; and said means enabling attachment ofthe power means comprises a saddle rigidly fastened to said side membersand said one wall, and an upstanding post rigidly secured to said saddleand said one wall; and means in said post enable an adjustableconnection to an end of a connecting rod, permitting shifting of saidconnection toward and away from said saddle 33 A pipe will reducing rollstand, as defined in claim 10, wherein said rocking lever meanscomprises two parallel laterally spaced apart lever members verticallydisposed in balanced disposition on each side of said feed path axis andthe upper lever arm connection to said connecting rod means disposedsaid connecting means in vertical planar alignment with and above thefeed path axis to provide a lateral force balance drive connection tothe roll stand.

34. A pipe mill reducing roll stand as defined in claim 20, wherein saidseparator includes a set of at least three contoured roller pressuretracks along each of which one of said rollers is rolled during a pipereducing reciprocation of said roll stand and wherein each of saidrollers has a constant profile pass groove throughout the 360circumference of the roller, the cross section radius of said passgroove being substantially equal to the radius of the finished outsidediameter surface of a pipe being reduced, and both circumferential edgesof each roller pass groove being rolled out to provide a relief from theradius of the pass groove, the roll out angle resulting in a reducfionwithin the range of from 2 to 15 in the angle of intersection between atangent to a constant radius pass groove at a circumferential edge and aline parallel to the roller axis at the circumferential edge.

35. A pipe mill reducing roll stand as defined in claim 34, wherein theroller pass groove bears against and rolls along the associatedcontoured roller pressure track.

36. A pipe mill reducing roll stand as defined in claim 34, wherein eachroller has large diameter cylindrical stub shaft shanks approximatingthe diameter of the base of the roller roll pass groove and said rollershanks of each roller bear against and roll along spaced apart trackflanges on an associated one of said set of contoured roller pressuretracks.

, v NI E STATES ,PIATENT OFFICE CERTIFICATE OF CORRECTION vi 3,673,840Dated, Ju1 4, 1972 Patent No.

lnvntofls) A'. I"; Tselikov" et a1 Itis certified that-error app ea rain the ahci re identified patent and that said Letters Patent are he ehycorrected asshown below:

' On Title page, in title, after "Pipe" insert --Mill-.

- in Inventors, "Vladimisovich" should be -Vladimirovich--. v

I in Assignee, change "Nau chno Issledovat k---Nauchno-'I'ssledcvatelsky m I 7 Col. 1, line 50, delete "end. Animproved, and more reliable, parallel roll stand".

, line 75, change "driven" to --drive--. I

Col. 6, line 51, change "jdke" to --yoke--.

Col. 13, line 3, change "crossdse'ction" to--cross-- section-.

Claim 21, line 16, change "between" t'o --above--.

Signed and sealed this 2nd day of January 1973.

(SEAL) Attest:

EDWARD M. FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissionerof Pater FORM PO-1050 (10-69) USCOMWDC 376m, 1 U.S GOVERNMENT PRINTINGOFFICE [9B9 0J65-Z

1. A pipe mill reducing roll stand adapted to reciprocate along opposed,spaced apart tracks, disposed parallel to a pipe blank feed path axis,said roll stand comprising: a carriage with bearing means adapted toengage the tracks and reciprocally mount said stand on the tracks; athick walled roller mounting head rigidly fastened in said carriagecoaxial with the feed path axis; a roller separator slidably mountedwithin said head for reciprocation along said feed path axis relative tosaid head; working rollers in said separator spaced at equi-angularlocations around said axis; means resiliently mounting each of saidworking rollers for limited radial shift in said separator comprisingbearing inserts with surfaces embracing cylindrical surfaces on saidworking roller, first guide means in said separator, second guide meanson said bearing inserts cooperating with said first guide means toconfine said bearing inserts and associated roller as a unit and permitradial reciprocation of said unit between limit positions, coil springsdisposed between said bearing inserts and said separator biasing saidunit radially outward, and abutment means on said separator defining thelimit positions of said unit; and means on said carriage enablingattachment of reciprocable drive means.
 2. A pipe mill roll stand, asdefined in claim 1, wherein said inserts have spring seat recessesfacing the center of said separator, said springs are small compressioncoil springs seated in associated ones of said recesses, and saidabutment means include abutment portions on the interior of saidseparator, spaced radially from its axis, to provide the other seatingsurfaces for said springs.
 3. A pipe mill roll stand, as defined inclaim 2, wherein said rollers have a groove working profile which isconstant along the roller perimeter and cylindrical journals on eachside of said working groove; each bearing insert in a block with twolegs, contoured to bear on the two shanks, bridging the working profile;two of said blocks and an embraced roller slide radially in a windowprovided in said separator; and a removable lock plate on the outer sideof said separator overlays the window and retains said inserts andassociated roller within said separator.
 4. A pipe mill roll stand, asdefined in claim 1, wherein said carriagE has a frame construction withtwo apertured end walls; said roll head is a thick-walled cylinder whichis inserted through the apertures in both of said end walls; removablemeans, secured to at least one of said end walls, cooperate with saidcylinder to rigidly maintain said cylinder in accurate angular and axialdisposition in said carriage and permit rapid removal and replacement.5. A pipe mill roll stand, as defined in claim 4, wherein said carriageframe has side members; and said means enabling attachment of the powermeans comprises a saddle rigidly fastened to said side members and saidone wall, and an upstanding post rigidly secured to said saddle and saidone wall; and means in said post enable an adjustable connection to anend of a connecting rod, permitting shifting of said connection towardand away from said saddle.
 6. A pipe mill roll stand, as defined inclaim 5, wherein said drive means has parallel linkage means, includingsaid connecting rod and link means connected to said separator, wherebyreciprocable shifting of said drive means provides synchronized shiftingof the thick-walled cylindrical head and of the roll separator atdifferent rates.
 7. A pipe mill roll stand, as defined in claim 6,wherein said head includes contoured working roller track gibs securedin said head against axial and angular shift and along which saidfloating working rollers roll during reciprocation of said head.
 8. Apipe mill roll stand, as defined in claim 7 wherein means resilientlysecure and bias said track gibs to the inside of the wall of said head,wedge means are disposed between each track gib and the head cylinderwall so that fore and aft shifting of said wedge means can change theradial disposition of said track gibs relative to the axis of said headcylinder; adjustment means on the front end of said head are attached tosaid wedge means to enable simultaneous adjustment shifting of all saidwedge means.
 9. A pipe mill roll stand, as defined in claim 8, whereinsaid wedge adjustment means includes: an axially shiftable ring bushingin the front end of said head connected to each said wedge means, saidbushing having screw threads on its outer periphery; a ring gear withinternal screw threads engaged with the screw threads on said bushingand journalled in the front end of said head against axial shift; and aring gear operator including a spur gear journalled in said end of saidhead and meshed with said ring gear.
 10. A pipe mill support means andreducing roll stand reciprocably carried on said support means whichincludes opposed, spaced apart tracks, disposed parallel to a pipe blankfeed path axis; said roll stand comprising a carriage with bearing meansadapted to engage the tracks and reciprocally mount said stand on thetracks, a thick walled roller mounting head rigidly fastened in saidcarriage coaxial with the feed path axis, a roller separator slidablymounted within said head for reciprocation along said feed path axisrelative to said head, working rollers in said separator spaced atequi-angular locations around said axis, and means on said carriageenabling attachment of reciprocable connecting rod means; a verticalrocking lever disposed in said support means adjacent the rear end ofsaid roll stand with its rocking axis below the feed path axis and anupper arm projecting to an end connector located above the feed pathaxis; connecting rod means connected between said upper lever arm andsaid roll stand.
 11. A pipe mill support and roll stand, as defined inclaim 10, wherein said carriage has a frame construction with twoapertured end walls; said roller head is a thick-walled cylinder whichis inserted through the apertures in both of said end walls; removablemeans, secured to at least one of said end walls, cooperate with saidcylinder to rigidly maintain said cylinder in accurate angular and axialdisposition in said carriage and permit rapid removal and replacement.12. A pipe mill support and roll stand, as defined in claim 11, whereinsaid carriage frame has side members; and said means enabling attachmentof the connecting rod means comprises: a saddle rigidly fastened to saidside members and said one wall, and an upstanding post rigidly securedto said saddle and said one wall; and means in said post enable anadjustable connection to an end of a connecting rod, permitting shiftingof said connection toward and away from said saddle.
 13. A pipe millsupport and roll stand, as defined in claim 12, wherein said connectingrod means has parallel linkage means, including said connecting rod andlink means connected to said separator, whereby rocking of said leverprovides synchronized shifting of the head and of the separator atdifferent rates.
 14. A pipe mill support means and roll stand as definedin claim 10, wherein said connecting rod means includes link meansconnected between said end connector and said carriage, and adjustablelink means connected between said upper arm means and said separator.15. A pipe mill support and roll stand as defined in claim 14, whereinsaid link means between said end connector and said carriage has anadjustment device at the connection to the upper lever arm and a secondadjustment device at the connection to the carriage.
 16. A pipe millsupport means and roll stand as defined in claim 10, wherein saidrocking lever means has upper and lower lever arms and its rocking axisis located intermediate the ends of said upper and lower lever arms andthe end of said lower lever arm provides means for connection to areciprocating power drive means.
 17. A pipe mill support means and rollstand as defined in claim 16, wherein said lever means includes at leasttwo laterally spaced apart elongate members extended upwardly inbalanced disposition on each side of the feed path axis and the lowerportions of said elongate members constitutes a forked lower lever armand include said means providing for a connection to a reciprocatingpower drive means.
 18. A pipe mill support and roll stand as defined inclaim 10, wherein the top portion of said roll stand includes attachmentmeans providing drive transfer connection between said carriage and atleast a portion of said connecting rod means.
 19. A pipe mill supportand roll stand as defined in claim 18, wherein said carriage comprisesframe structure and said attachment means is an upstanding connectorlink rigidly secured on top of said frame structure.
 20. A pipe millsupport means and reducing roll stand as defined in claim 10, whereinsaid roll stand includes means mounting each of said working rollers forlimited radial shift in said separator comprising bearing inserts withsurfaces embracing cylindrical surfaces on said associated workingroller, first guide means in said separator, second guide means on saidbearing inserts cooperating with said first guide means to confine saidbearing inserts and associated roller as a unit and permit radialreciprocation of said unit between limit positions.
 21. A pipe millsupport means and reducing roll stand reciprocably carried on saidsupport means which includes opposed, spaced apart tracks, disposedparallel to a pipe blank feed path axis; said roll stand comprising acarriage with bearing means adapted to engage the tracks andreciprocally mount said stand on the tracks, a thick walled rollermounting head rigidly fastened in said carriage coaxial with the feedpath axis, a roller separator slidably mounted within said head forreciprocation along said feed path axis relative to said head, workingrollers in said separator spaced at equi-angular locations around saidaxis, and means on said carriage enabling attachment of reciprocableconnecting rod means; a vertical rocking lever means disposed in saidsupport means adjacent the rear end of said roll stand with its rockingaxis below the feed path axis and an upper lever arm means withconnection means located between the feed path axis; and connecting rodmeans connectEd between said upper lever arm connection means and saidroll stand, including adjustable link means connected to said carriage.22. A pipe mill support and roll stand as defined in claim 21, whereinsaid adjustable link means has a first adjustment device at theconnection to the upper lever arm and a second adjustment device at theconnection to the carriage.
 23. A pipe mill support means and roll standas defined in claim 21, wherein said connecting rod means includes asecond adjustable link means connected between said upper lever armmeans and said separator.
 24. A pipe mill support and roll stand, asdefined in claim 21, wherein said carriage has a frame construction withtwo apertured end walls; said thick-walled roller mounting head isinserted through the apertures in both of said end walls; means, securedto at least one of said end walls, cooperate with said roller mountinghead to rigidly maintain said head in accurate angular and axialdisposition in said carriage and permit rapid removal and replacement.25. A pipe mill support and roll stand, as defined in claim 24, whereinsaid carriage frame has side members; and said means enabling attachmentof the connecting rod means comprises: a saddle rigidly fastened to saidcarriage frame and an upstanding post rigidly secured to said saddle anda said end wall; and said adjustable link means includes connectingmeans in said post enabling an adjustable connection permitting shiftingof said connection toward and away from said saddle.
 26. A pipe millsupport and roll stand, as defined in claim 21, wherein said connectingrod means has parallel linkage means, including said adjustable linkmeans and link means connected to said separator, whereby rocking ofsaid lever provides synchronized shifting of the head and of theseparator at different rates.
 27. A pipe mill support and roll stand asdefined in claim 21, wherein the top portion of said roll stand includesattachment means providing drive transfer connection between saidcarriage and said adjustable link means.
 28. A pipe mill support androll stand as defined in claim 27, wherein said carriage includes framestructure and said attachment means includes an upstanding connectorlink rigidly secured on top of said frame structure, said attachmentmeans further including a pivot connection portion adjustably shiftabletoward and away from said carriage in said upstanding link.
 29. A pipemill reducing roll stand adapted to reciprocate along opposed, spacedapart tracks, disposed parallel to a pipe blank feed path axis, saidroll stand comprising: a carriage with bearing means adapted to engagethe tracks and reciprocally mount said stand on the tracks; a thickwalled roller mounting head rigidly fastened in said carriage coaxialwith the feed path axis; a roller separator slidably mounted within saidhead for reciprocation along said feed path axis relative to said head;working rollers in said separator spaced at equi-angular locationsaround said axis; means mounting each of said working rollers forlimited radial shift in said separator comprising bearing inserts withsurfaces embracing cylindrical surfaces on said working roller, firstguide means in said separator, second guide means on said bearinginserts cooperating with said first guide means to confine said bearinginserts and associated roller as a unit and permit radial reciprocationof said unit between limit positions; and means on the top portion ofsaid roll stand carriage enabling attachment of drive means forreciprocation of said carriage.
 30. A pipe mill reducing roll stand asdefined in claim 29, wherein said means on the top portion of saidcarriage includes an upstanding connector link rigidly secured on top ofsaid carriage and a pivot connection portion adjustably shiftable towardand away from said carriage in said upstanding link.
 31. A pipe millreducing roll stand, as defined in claim 29, wherein said carriage has aframe construction with two apertured end walls; said roller mountinghead is a thick-walled cylinder which is inserted through the aperturesin both of said end walls; removable means, secured to at least one ofsaid end walls, cooperate with said cylinder to rigidly maintain saidcylinder in accurate angular and axial disposition in said carriage andpermit rapid removal and replacement.
 32. A pipe mill roll stand, asdefined in claim 31, wherein said carriage frame has side members; andsaid means enabling attachment of the power means comprises a saddlerigidly fastened to said side members and said one wall, and anupstanding post rigidly secured to said saddle and said one wall; andmeans in said post enable an adjustable connection to an end of aconnecting rod, permitting shifting of said connection toward and awayfrom said saddle.
 33. A pipe will reducing roll stand, as defined inclaim 10, wherein said rocking lever means comprises two parallellaterally spaced apart lever members vertically disposed in balanceddisposition on each side of said feed path axis and the upper lever armconnection to said connecting rod means disposed said connecting meansin vertical planar alignment with and above the feed path axis toprovide a lateral force balance drive connection to the roll stand. 34.A pipe mill reducing roll stand as defined in claim 20, wherein saidseparator includes a set of at least three contoured roller pressuretracks along each of which one of said rollers is rolled during a pipereducing reciprocation of said roll stand and wherein each of saidrollers has a constant profile pass groove throughout the 360*circumference of the roller, the cross section radius of said passgroove being substantially equal to the radius of the finished outsidediameter surface of a pipe being reduced, and both circumferential edgesof each roller pass groove being rolled out to provide a relief from theradius of the pass groove, the roll out angle resulting in a reductionwithin the range of from 2* to 15* in the angle of intersection betweena tangent to a constant radius pass groove at a circumferential edge anda line parallel to the roller axis at the circumferential edge.
 35. Apipe mill reducing roll stand as defined in claim 34, wherein the rollerpass groove bears against and rolls along the associated contouredroller pressure track.
 36. A pipe mill reducing roll stand as defined inclaim 34, wherein each roller has large diameter cylindrical stub shaftshanks approximating the diameter of the base of the roller roll passgroove and said roller shanks of each roller bear against and roll alongspaced apart track flanges on an associated one of said set of contouredroller pressure tracks.